Automatic switch



Feb. 1, 1944. v B. D. WILLIS 2,340,445

AUTOMATIC SWITCH Filed Afiril 13, 1942 QShe ts- Sheet 1' I new T AUTOMATIC SWITCH IOO INVENTOR. I BERNARD D WILLIS DECEASED BY W WALTER OWEN, EXEGUTOR ATTORN EYS Feb. 1, 1944.

B. D. WILLIS 2,340,445

AUTOMATIC} SWITCH Filed April 13. 1942 9 Sheets-Sheet 2 1 ENTOR. BERNARD o.wn |s DECEAFD BY w WALTER OWEN, EXEGUTOR BM) H ATTORNEYS Feb. 1, 1944. B. D. WILLIS 2,340,445

AUTOMATIC SWITCH 0: soo 602 U LIOS -c INVENTOR.

BERNARDD. WILLIS DECEASED BY w WALTER owtN, EXEOUTOR x M m ATTORNFYS Feb. 1, 1944.

Y B. D. WILLIS AUTOMATIC SWITCH Filed April 13, 1942 9 Sheets-Sheet '7 FR b O O O 0 llll l. 0 o o o' oo o o o l l I l I l l ll. l l l l o o o o o.|||||||.|o o o o 9.||||.||| 6 mm 7 m m mo l 1 l l I I In |||||||||||||||l|||||||l m l|||| e m N4 mw mm Q Q &5 Q 4 mo @0 mu-Q olulllllfo 0c 0 onlllllllvlll\.||.|||l|||||||:o o o 0 o llll 0 o o 0 c :6 0

Na RIP ZN- 91w ATTORNEYS Patented Feb. 1, 1944 Bernard D. Willis, deceased, late of Oak Park, 111.,

by Wm. Walter Owen, executor, Elgin, 111., assignor to Automatic Electric Laboratories, Inc., a corporation of Delaware Application April 13, 1942, Serial No. 438,695

14 Claims.

The present invention relates to switching systems and more particularly to automatic switches for telephone systems of the character of that disclosed in the copending application of Bernard D. Willis, Serial No. 377,835, filed February 7, 1941.

While the automatic switches utilized in the telephone system disclosed in the Willis application mentioned are entirely satisfactory in operation, they are of more complicated construction and arrangement than is desirable.

Accordingly one of the principal objects of the present invention is to provide an improved automatic switch of the character noted which is of relatively simple and compact construction and arrangement.

Another object of the invention is to provide an improved automatic switch including a contact controlling member having both primary and secondary movements along an associated single row of contacts.

A further object of the invention is to provide an improved automatic switch of the primarysecondary motion type, wherein the speeds at which the respective primary and, secondary motions thereof take place are so correlated that the switch selects one group of contacts from the associated contact bank per unit time interval during the primary motion thereof and then selects one contact from the previously selected group of contacts per unit time interval during the secondary motion thereof.

A still further object of the invention is to provide an improved automatic switch of the primary-secondary rotation type, wherein the primary and secondary rotations thereof take place uniformly at different speeds along a single annular path.

In general, the objects set forth above are attained in accordance with the present invention by providing an automatic switch comprising a contact bank including a plurality of groups of contacts arranged in a row, each of the groups including N contacts, and a contact controlling member mounted for both primary and secondary movements along the row of contacts. Also the switch comprises means for imparting prima'ry movement to the member at a substantially uniform speed NS, whereby the member selects from the contact bank one group of contacts per unit time interval during the primary movement thereof, and means for imparting secondary movement to the member at a substantially uniform speed S, whereby the member selects from the previously selected group of contacts one contact per unit time interval during the secondary movement thereof. More particularly, the groups of contacts in the contact bank are arranged in an annular row and the contact controlling member is mounted for both primary and secondary rotations along the annular row of contacts. Also primary rotation is imparted to the member at a substantially uniform speed N 0 and secondary rotation is imparted to the member at a substantially uniform speed 0.

Further features of the invention pertain to the particular arrangement of the mechanical elements of the automatic switch, whereby the above-outlined and additional operating features are attained.

The invention, both as to its organization and method of operation, together with further objects and advantages thereof, will best be understood by reference to the following specification taken in connection with the accompanying drawings, in which Figure l is a side elevational view, partly in section, of an automatic switch embodying the present invention; Fig. 2 is a sectional view, taken along the line 2-2 in Fig. 1, of the gear train incorporated in the automatic switch shown in Fig. 1; Fig. 3 is a sectional view, similar to Fig. 2, of a modified form of the gear train, which is adapted to be incorporated in the automatic switch shown in Fig. 1; Fig. 4 is a diagrammatic illustration of one form of the contact bank of the automatic switch, which is utilized when the gear train shown in Fig. 2 is incorporated therein; Fig. 5 is a diagrammatic illustration of a modified form of the contact bank of the automatic switch, which is utilized when the gear train shown in Fig. 3- is incorporated therein; Fig. 6 is a diagrammatic illustration of one form of the wiper set of the automatic switch, which is utilized when either of the contact banks shown in Figs. 4 and 5 is employed; Fig. 7 is a diagrammatic illustration'of another modified form of the contact bank of the automatic switch, which is utilized when the gear train shown in Fig. 2 is incorporated therein; Fig. 8 is a diagrammatic illustration of a further modified form of the contact bank of the automatic switch, which is utilized when the gear train shown in Fig. 3 is incorporated therein; Fig. 9 is a diagrammatic illustration of a modified form of the wiper set of the automatic switch, which is utilized when either of the contact banks shown in Figs. 7 and 8 is employed; Figs. 10 and 11, taken together, illustrate diagrammatically one form of a telephone system embodyingthe present invention and comprising an automatic switch incorporating the gear train shown in Fig. 2 and utilizing either of the contact banks shown in Figs. 4 and 7; Figs. 10 and 12, taken together, illustrate diagrammatically a modified form of the telephone system and comprising an automatic switch incorporating the gear train shown in Fig. 3 and utilizing either of the contact banks shown in Figs. 5 and 8; Figs. 13 and 14, taken together, illustrate diagrammatically another modified form of the telephone system and comprising an automatic switch incorporating the gear train shown in Fig. 2 and utilizing either of the contact banks shown in Figs. 4 and '7; andFigs; l3 and 15, taken together, illustrate diagrammatically a further modified form of the telephone system and comprising an automatic switch incorporating the gear train shown in Fig. 3 and utilizing either of the contact banks shown in Figs. 5 and 8.

Referring now more particularly to Figs. 1 and 2 of the drawings there is illustrated an automatic switch .Ir'lfi embodying the present invention, which comprises an upper supporting channel IUI, a lower supporting channel It: and a substantially U-shaped supporting bracket IE3, the flanges of the Supporting channels IE! and I02 being directed toward each'ot'her and secured together in lace between the outer ends of the legs of the supporting bracket IiI3 by a plurality of screws I84. Alsothe switch I comprises an operating shaft I95 suitably journaled in a bearing provided in the bottom wall of the lower supportingchannel I82,a carriage IIIB, a gear bracket IEII. and a gear train supported by the gear bracket I87 and interposed between the operating shaft I95 and the carriage I05. More particularly, the carriage I96 is in the form of a disk disposed above the gear bracket IE1 and surrounding the operating shaft I; while the gear bracket IIJ'I surrounds the operating shaft I05 "and is of substantially U-shape, including upper and lower plates hit and I99 and a connecting strap I IG; Also a flexible friction plate III surrounds the operating shaft I35 and is rigidly secured to the lower plate I09 of the gear bracket IIB'I by a number of rivets II2. Further a collar H3 surrounds the operating shaft I05 and is rigidly secured to the upper surface of the carriage 165 by a number of screws H4. The carriage I85 and the supported collar I I3, as well as the gear bracket I01 and the supported friction plate H I, areheld in assembled relation upon the operating shaft I05 by an arrangement comprising two collars H5 and III; respectively carried adjacent the upper and lower ends of the operating shaft Hi5. More particularly, the collar I I5 is secured to the-upper end of the operating shaft I85 by a set screw I I? and bears upon the adjacent upper surface of the bottom wall of the lower supporting channel I92; while the collar H6 is secured to the lower end of the operating shaft IIIS by a set screw H8 and bears upon the adjacent lower surface of the friction plate I! I.

the upper and lower plates I08 and I09 of the The collar H3 is spaced from the lower surface of the bottom wall of the lower supporti gear bracket Iil'I, two transmission pinions I22 and I23 rotatably mounted on two pins I24 and I25 extending between the upper and lower plates I98 and I09 of the gear bracket I01 and a rin gear I25 rigidly secured to the lower surface of the carriage I95 adjacent the peripheral edge thereof. The teeth on the drive gear I2I mesh the teeth on the transmission pinions I22 and I23 disposed on opposite sides thereof; while the teeth on the transmission pinions I22 and IE3 mesh the internal teeth on the ring gear I26. Finally it is noted that the opposite ends of the flexible friction plate III engage the lower surface of the ring gear I26 in order normally to lock the ring gear I26 and consequently the carriage II'IE directly to the operating shaft m5.

Also the switch IIlIl comprises shift mechanism I38 for controlling the gear train and conseouently the speed of rotation of the carriage I06. The shift mechanism I36 comprises a shift magnet MISI, provided with a core I32, a cup-shaped field element I33 and a movable armature Iii I. Also the shift mechanism I39 includes a friction ring I35. The shift magnet MISI, the core I32 and the field element I33 comprise a unit which is suitably secured in a centrally disposed U- shaped bend I 36 formed in the supporting bracket I98; while the armature I34 surrounds the operating shaft IE5 and is secured to the flexible friction plate I I I adjacent the outer ends thereof by two clips IiI'I and I 33. The friction ring I35 is suitably secured to the supporting bracket IE3 in surrounding relation with respect to the armature I34 and is arranged below the outer ends of the friction plate III in spaced relation with re spect thereto. At this point it is noted that the outer ends of the friction plate III normally ongage the lower surface of the ring gear I25, but are adapted to engage the upper surface of the friction ring I35 when the friction plate III is flexed due to movement of the armature I35 in a downward direction, in a manner more fully explained hereinafter.

Further the switch Ifiil comprises a stub shaft Mil suitably journaled in a bearing provided in the top wall of the upper supporting channel IfiI and arranged in alignment with the operating shaft 5%. The upper end of the stub shaft I43 carries a bevel gear I4I which bears against the upper surface of the top wall of the upper supporting channel Iill. A collar I42 is secured to the stub shaft I by a set screw I43 and bears against the lower surface of the top wall of the upper supporting channel IIJI.

Further the switch I00 comprises clutch mechanism Ifib including a go magnet MISI and a stop magnet MI52. The go magnet MIEI includes a core I53 carrying two spaced-apart field elements I54 on the opposite ends thereof; while the stop magnet MI'52 includes a core I55 carrying two spaced-apart field elements I55 on the opposite ends thereof. The core IE3 is secured to two nonmagnetic brackets I51 by two screws I58, which brackets I51 are suitably secured to the top wall of the upper supporting channel IfiI Similarly, the core I55 is secured to two nonmagnetic brackets I59 by two screws Itfi, which brackets I59 are suitably secured to the bottom wall of the lower supporting channel I623. The upper end of the operating shaft I55 carries a tubular collar IEI slidably mounted thereon, a pin I62 being fixed to the operating shaft I and arranged in a longitudinally extending slot I63 formed in the tubular collar I6I. The lower end of the tubular collar I6I is normally supported upon the collar H5 and the upper end thereof carries an annular flange I64 formed of magnetic material. A drive plate I65 is secured to the lower endof the stub shaft I40 by a set screw I66 and arranged above and in spaced relation with the annular flange I64.

The switch I is supported as a whole in cooperating relation with a drive shaft I61 upon two external supports I68 engaging the lower surface of the top wall and the adjacent flanges of the upper supporting channel IOI. It is noted that the drive shaft I61 is common to a plural ity of switches of the character of the switch I00 and is suitably journaled in a number of bearing brackets I69 carried by an external support I10. More particularly, the drive shaft I61 carries a bevel gear I1I which is arranged to mesh the bevel gear I4I carried on the upper end of the stub shaft I40 when the switch I00 is supported in place upon the external supports I 68, in the manner noted above. Also the witch I00 is supported in cooperating relation with respect to a contact bank support I12 which carries a contact bank, not shown, the contact bank support I12 being disposed between the legs of the supporting bracket I63 and carried by two external supports I13. The external supports I13 and the contact bank support I12 engage the legs of the supporting bracket I03, thereby positively to position the switch I00. Further it is noted that the carriage I06 supports a Wiper set, not shown, which cooperates with the contact bank carried by the contact bank support I12.

When the switch I00 is completely released the shift magnet MI3I is deenergized, whereby the flexible friction plate III is biased, due to its inherent resiliency, into engagement with the lower surface of the ring gear I26 in order to lock the ring gear I26 and consequently the carriage I06 directly to the operating shaft I05, as previously noted. Also, at this time, the wiper set carried by the carriage I06 occupies its normal position with respect to the contact bank carried by the contact bank support I12, in a manner more full explained hereinafter. Fur.-

thermore, the go magnet M15I and the stop magnet Ml52 are normally deenergized, whereby the tubular collar I6! occupies its normal position engaging the collar H and the annular flange I64 carried by the tubular collar I6I disengages the associated drive plate I65. Finally the drive shaft I61 is rotated at a constant speed in the clockwise direction, as viewed toward the right, in order to drive the stub shaft I40 at a constant speed in the clockwise direction, as viewed from the top. Hence, at this time, the stub shaft I40 and the drive plate I65 carried thereby are rotated in the clockwise direction above the annular flange I04 carried by the tubular collar I61.

In order to operate the switch I00, thereby to cause the wiper set carried by the carriage I06 to select a particular group of contact sets in the associated contact bank. the go magnet Ml5l is first energized and retained energized for a corresponding given time interval, depending upon the speed of rotation of the stub shaft I40, this given time interval comprising one or more unit time intervals, as explained more fully hereinafter; and, at the conclusion of this given time interval, the go magnet MEEI is deenergized and the stop magnet MI52 is energized. When the go magnet Ml5l is thus energized the field elements I54 thereof attract the annular flange I64, thereby to cause the annular flange I64 to move the carriage I06 in the clockwise direction, which upwardly into frictional engagement with the drive plate I65, the pin and slot connection I62--I63 between the operating shaft I05 and the tubular collar I6I accommodating this movement of the tubular collar "SI and the annular flange I64 carried thereby. When the annular flange I64 is thus moved by the go magnet MI5I into frictional engagement with the drive plate I the operating shaft I05 is clutched to the stub shaft I40 and is rotated in the clockwise direction.

At this time the operating shaft I05 is directly locked to the ring gear I26 and consequently to the carriage I06 by the resilient friction plate III, whereby the carriage I06 is rotated in the clockwise direction with the operating shaft I05 at the same speed. During this rotation of the operating shaft I05 the gear bracket I'01 is rotated therewith, whereby the transmission pinions I22 and I23 remain stationary upon the associated pins I24 and I25, but are revolved about the operating shaft I05 with the gear bracket I01. As the carriage I06 is thus rotated in the clockwise direction the wiper set supported thereby is moved continuously with respect to the groups of contact sets in the associated contact bank, whereby the different groups of contact sets are progressively selected by the wiper set. More particularly, the speed of rotation of the operating shaft I05 is so related, with respect to the position of the groups of contact sets in the contact bank associated with the wiper set carried by the carriage I05, that the wiper set selects one group of contact sets in the associated contact bank during each unit time interval. Thus, at the conclusion of the first, second etc. unit time intervals, the wiper set has selected the corresponding first, second etc. groups of contact sets in the associated contact bank.

At the conclusion of the given time interval the go magnet MI5I is deenergized and the stop magnet MI52 is energized, as previously noted,

whereupon the field elements I56 of the stop magnet MI 52 attract the annular flange I64 causing the tubular collar I6I and the annular flange I64 carried thereby to be moved downwardly, the

pin and slot connection I62I63 between the operating shaft I05 and the tubular collar I6I facilitating this movement. At this time the stop magnet MI52 is retained energized, thereby to retain the annular flange I64 out of engagement with the drive plate I65 and in locked engagement with the field elements I56. As long as the'stop magnet MI52 is retained energized, the annular flange I64 is retained in locked engagement with respect to the field elements I56, thereby to prevent movement of the carriage I06 and. consequently the wiper set carried thereby.

At the conclusion of the rotary movement of motion constitutes the primary motion of the switch I00, as explained above, the shift magnet MI3I is energized. When the shift magnet MI3I is thus energized the armature I34 is attracted by the cup-shaped field element I33 and is moved downwardly, whereby the straps I31 and I38 con necting the armature I34 to the flexible friction plate I II flex the outer ends of the friction plate III downwardly out of engagement with the lower surface of the ring gear I26 and into en gagement with the upper surface of the friction ring I35. When the armature I34 is thus operated in order to flex the friction plate I I I, a explained above, thering gear I26 and consequently the carriage I06 are unlocked from the operating shaft I05; and the friction plate III and consequently the gear bracket I01 are locked to the stationary friction ring I35.

After the switch I has been operated in the manner described above, thereby to cause the wiper set carried by the carriage I06 to select one of the groups of contact sets in the associated contact bank carried by the contact bank support I12, the switch I00 is operated further in order to cause the wiper set to select a particular contact set in the previously selected group of contact sets in the associated contact bank. In order to accomplish this end, the stop magnet MI52 is first deenergized and then the go magnet MII is energized and retained energized for a corresponding given time interval, depending upon the speed of rotation of the stub shaft I40, this given time interval comprising one or more unit time intervals, as explained more fully hereinafter; and at the conclusion of this given time interval the go magnet MI5I is deenergized and the stop magnet M I52 is energized. When the stop magnet MI52 is thus deenergized the field elements I56 release the annular flange I04; and when the go magnet MI5I is thus energized the field elements I54 attract the annular flange I64, thereby again to clutch the annular flange I54 to the drive plate I65, in the manner previously explained; whereby the operating shaft I05 is again rotated in the clockwise direction with the stub shaft I40. The rotation of the operating shaft I05 in the clockwise direction eifects rotation of the drive gear I'2I in the clockwise direction, whereby the transmission pinions I22 and I23 are rotated in the counterclockwise direction about the pins I24 and I25 extending between the upper and lower plates I08 and I09 of the gear bracket I01 due to the fact that the gear bracket I01 is locked by the friction plate III to the stationary friction ring I35 against rotation in the clockwise direction. The rotation of the transmission pinions I22 and I23 in the counterclockwise direction about the pins I24 and I25 effects rotation of the ring gear I26 in the counterclockwise direction, whereby the carriage I00 is driven continuously in the counterclockwise direction during the given time interval mentioned.

As the carriage I 05 is thus rotated in the counterclockwise direction the wiper set carried thereby successively engages the individual contact sets in the previously selected group of contact sets in the associated contact bank. The gear train interposed between the operating shaft I05 and the carriage I06 has a transmission ratio, as determined by the number of teeth disposed about the periphery of the drive gear I2I and the number of teeth disposed about the interior of the ring gear I26, of :1; whereby the operating shaft I05 is rotated in the clockwise direction ten times as fast as the rotation of the carriage I00 in the counterclockwise direction when the gear train is effective. At the conclusion of any given number of unit time intervals the wipor set engages a corresponding individual contact set in the previously selected group of contact sets in the associated contact bank. Thus at the conclusion of the first, second etc. unit time intervals the wiper set engages the corresponding first, second etc. individual contact sets in the previously selected group of contact sets in the associated contact bank.

At the conclusion of the given time interval the go magnet MI5I is deenergized and the stop magnet MI52 is again energized, as previously noted; whereupon the field elements I54 release the annular flange I64 and the field elements I50 attract the annular flange I04 in order to cause the annular flange I64 to be locked to the field elements I55, in the manner previously explained.

At this time the wiper set carried by the car riage I05 has selected a particular group of contact sets in the associated contact bank corresponding to the first time interval mentioned and a particular individual contact set in the previously selected group of contact sets in the associated contact bank corresponding to the second time interval mentioned, thereby to establish a connection to the particular selected individual contact set. At the conclusion of the rotary movement of the carriage I 05 in the counter-clockwise direction, which motion constitutes the secondary motion of the switch I00, as explained above, the shift magnet MI3I and the stop magnet MI52 are retained energized.

In view of the foregoing explanation of the mode of operation of the switch I00 first to select a particular group of contact sets and then to select a particular individual contact set in the previously selected group of contact sets in the associated contact bank, it will be understood that the carriage I 06 is first rotated in the clockwise direction, the primary movement of the switch I00, at a speed of I08; then the carriage I06 is rotated in the counterclockwise direction, the secondary movement of the switch I00, at a speed of IS. Accordingly the switch I00 operates during the primary movement of the carriage I 00 to select one group of contact sets per unit time interval and then operates during the secondary movement of the carriage I06 to select one contact set from the previously selected group of contact sets per unit time interval.

In order completely to release the switch I00 the shift magnet MI3I and the stop magnet MI 52 are first deenergized and the go magnet MI5I is energized. When the shift magnet MI3I is thus deenergized the armature I34 is released by the cup-shaped field element I33, whereby the friction plate III moves the armature I34 upwardly out of engagement with the cup-shaped field element I33 due to its own resiliency. Furthermore, the outer ends of the resilient friction plate III are moved upwardly out of engagement with the stationary friction ring I35 and into engagement with the ring gear I20, whereby the ring gear I25 and consequently the carriage I00 are again locked to the operating shaft I05 directly, as previously explained. When the stop magnet MI52 is thus deenergized the field elements I55 release the annular flange I64; and when the go magnet MI5I is thus energized the field elements I54 attract the annular flange I64, whereby the annular flange I 64 is moved upwardly into engagement with the drive plate I65, in the manner previously explained. At this time the operating shaft I05 is again clutched to the stub shaft I40 and is rotated in the clockwise direction, whereby the carriage I 06 and the wiper set carried thereby are rotated in the clockwise direction at the speed of I08, in the manner previously explained. Finally when the wiper set carried by the carriage I 06 is returned to its normal position the go magnet MI5I is deenergized and the stop magnet MI52 is energized. When the go magnet MI5I is thus deenergized the field elements I54 release the annular flange I64; and when the stop magnet MI52 is thus energized the field elements I55 attract the annular flange train comprises, in addition I64, whereby the annular fiange 164 is moved downwardly into locked engagement with the field elements I56, in the manner previously explained. At this time the operating shaft I05 is again declutched from the stub shaft I40. Ultimately the stop magnet MI52 is deenergized; however, the annular flange I64 remains in engagement with the field elements I56 due to the action of gravity in view of the fact that the go magnet MI5I is not energized at this time. At this time the switch I is completely released and available for further use.

In view of the foregoing explanation of the release of the switch I00 it will be understood that the carriage I06 thereof is rotated in the clockwise direction back to its normal position at the speed of I08 due to the fact that the shift magnet MI3I is deenergized at the beginning of the release period. Accordingly the carriage I06 of the switch I00 is rapidly returned, in the clockwise direction, to its normal position, in the manner explained above.

Referring now more particularly to Fig, 3 of the drawings, a modified form of the gear train,

-similar to the gear train shown in Fig. 2, is illustrated, which may be incorporated in the switch shown in Fig. 1. More particularly, this gear to the drive gear I2I and the ring gear I26, two sets of transmission pinions 30I, 302 and 304, 305 interposed between the operating shaft I and the carriage I06. More specifically, the drive gear I2I is rigidly secured to the operating shaft I05 and the transmission pinions 30I, 302, 303 and 304 are respectively rotatably mounted upon pins 3I I, 3I2,

314 and (H5 extending between the upper and lower plates I08 and I09 of the gear bracket I01. The teeth on the drive gear I2I mesh the teeth on the transmission pinions 30I and 302 disposed on opposite sides thereof; the teeth on the transmission pinions 301 and 302 respectively mesh the teeth on the transmission pinions 304 and 305 disposed on opposite sides thereof; while the teeth on the transmission pinions 304 and 305 mesh the teeth disposed about the interior of the ring gear I26 at opposite sides thereof.

The gear train shown in Fig. 3 may be substituted directly for the gear train shown in Fig.

"'2 in the switch shown in Fig. 1, in an obvious manner, in order to produce a modified switch I00. Considering now the operation of the modified switch I00 it is noted that the primary movement of the carriage I06 in the clockwise direction is the same as that previously described in view of the fact that, during the primary movement of the switch, the operating shaft I05 is locked directly to the ring gear I26 and consequently to the carriage I06, in the manner previously explained. However, the secondary movement of the carriage I06 is modified due to the interposition of the two sets of transmission pinions 30I, 302 and 304, 305 between the drive gear I2I and the ring gear I26. More particularly, when the armature I34 is operated in order to flex the outer ends of the friction plate III out of engagement with the ring gear I26 and into engagement with the stationary friction gear I35,

the operating shaft I05 is operatively connected to the carriage I06 through the gear train, as previously explained. At this time, rotation of the operating shaft I05 in the clockwise direction effects rotation of the drive gear I2I in the clockwise direction, and the consequent rotation of the transmission pinions 30I and 302 in the counterclockwise direction about the pins 3| I operating shaft and 3I2. The rotation of the transmission pin-. ions 30I and 302 in the counterclockwise direction about the pins 3 and 3I2 effects rotation of the transmission pinions 304 and 305 in the clockwise direction about the pins 314 and 3I5. Finally the rotation of the transmission pinions 304 and 305 in the clockwise direction about the pins 3I4 and 3I5 effects rotation of the ring gear I26 and consequently the carriage I06 in the clockwise direction. Accordingly, in the modified form of the switch I00, not only the primary movement of the carriage I06 but also the secondary movement thereof takes effect in the clockwise direction. Moreover, in the modified switch E08, the gear train interposed between the I05 and the carriage I06 has a transmission ratio, as determined by the number of teeth disposed about the periphery of the drive gear I2! and the number of teeth disposed about the interior of the ring gear I26, of 10:1; whereby the operating shaft I05 is rotated in the clockwise direction ten times as fast as the rotation of the carriage I06 in the clockwise direction, when the gear train is effective.

Thus, at the conclusion of any given number of unit time intervals, the wiper set engages a corresponding individual contact set in the previously selected group of contact sets in the associated contact bank. Thus, at the conclusion of the first, second, etc., unit time intervals, the wiper set engages the corresponding first, second, etc., individual contact sets in the previously selected group of contact sets in the associated contact bank.

The subsequent operation of the modified switch I00 at the conclusion of the second time interval, as well as the ultimate release thereof, is the same as those previously explained. More particularly, incident to the release of the modified switch, the carriage I06 is rotated in the clockwise direction back into its normal position.

In view of the foregoing explanation of the mode of operation of the modified switch I00 to select first a particular group of contact sets anld then a particular individual contact set in the previously selected group of contact sets in the associated contact bank, it will be understood that the carriage I06 is first rotated in the clockwise direction, the primary movement of the modified switch I00 at a speed of IOS; then the carriage I06 is rotated in the clockwise direction, the secondary movement of the modified switch I00, at a speed of IS. Accordingly the modified switch I00 operates during the primary movement of the carriage I06 to select one group of contact sets per unit time interval and then operates during the secondary movement of the carriage I66 to select one contact set from the previously selected group of contact sets per unit time interval. Also it will be understood that, during the release of the modified switch I00, the

carriage I06 thereof is rotated in the clockwise modified switch I00 is rapidly returned in the clockwise direction to its normal position, in the manner explained above.

Referring now more particularly to Figs. 4 and 6 of the drawings, there are illustrated diagrammatically one form of the wiper set 600 and the associated contact bank 400 of the switch I00 which may be utilized when the gear train, shown i-in Fig.2, is incorporated therein. ivi particu- Also the operating shaft I05 larly, the wiper set 000 is carried by the operating shaft I05 and comprises a number of wipers BOI,

602, etc. of the double-ended type; while the contact bank 400 is of the I-point type. More Specifically, the contact bank 400 comprises ten groups of contact sets; each group of contact sets comprises ten individual contact sets; and each individual contact set comprises a number of contacts respectively associated with the wipers '00I', 602, etc., of the wiper set 600.

, In this form of the Switch I00 the wiper set 600 is rotated continuously during the primary movement thereof in the clockwise direction, as indicated by the arrow P, from the normal position P0 successively through the positions PI, P2, etc., and P9 during the successive corresponding time intervals. Subsequently the Wiper set 600 is rotated continuously during the secondary movement thereof in the counterclockwise direc tion, as indicated by the arrow S, from the operatd position Pl, P2, etc., back toward the adjacent positionPfl, PI, etc., during the corresponding time intervals.

From an examination of the contact bank 400 shown in Fig. f1, it will be understood that, in order to operate the switch I 00 to select the contact sets II, I2, etc., the wiper set 600 is first rotated in the clockwise direction duringthe primary movement thereof from the normal position P0 engaging the contact set I0 to the position PI to engage the Contact set 20, and is then rotated in the counterclockwise direction during the secondary movement thereof from theipperated position PI toward the adjacent position P0 engage the contact sets II, I2, etc. Similarly, somer to operate the switch I00 to select the contact sets 0|, 02, etc., the wiper set 600 is first rotated in the clockwise direction during the primary movement thereof from the normal position P0 engaging the contact set I0 back to the position P0 to engage the contact set I0, and is then rotated in the counterclockwise direction during the secondary movement thereof from the operated position P0 toward the adjacent position P9 to engage the contact sets 0I, 02, etc. Ultimately, when the switch I00 is released the wiper set 600 is rotated in the clockwise direction from the engaged contact set back to the normal position P0 to engage the contact set I 0. A

operates elf-normechanism illustrated diacam IOI carried by the operating shaft I and an associated set of switch springs $405. The cam 40I comprises two projections 402 and 403 corresponding to the two normalpositions of the wiper set 500 while the set of switch springs S405 comprises a set of contacts 406 which is engaged when the wiper set 600 occupies either one of its normal positions and asset of contacts 410'! which is engaged when the wiper set 600 occupies other than one of its normal positions. This oiT-normal switch control mechanism is utilized in the switch I00 for a purpose more fully explained hereinafter.

} Referring now more particularly to Figs. 5 and 6 of the drawings, there are illustrated diagrammatically one form of the wiper set 600 and the associated contact bank 500 of the switch I00 which may be utilized when the gear train,

mal switch control grammatically as a ,shown in Fig. 3, is incorporated therein. More particularly, the wiper set 600 is carried by the operating shaft I05 and comprises a number of wipers 60I, 602, etc., of the double-ended type, as previously noted; while the contact bank 500 is of the I00-point type. More specifically, the

contact bank 500 comprises tn groups of contact sets; each" group of contact sets' comprises ten individual contact sets; and each individual coritact set comprises a number of cements respectively associated with the wipers Bill, 602, etc., of the wiper set 600. e

In this form of the switch I00 the wiper set 600 is rotated continuously during the primary movement thereof in" the clockwise direction, as indicated the arrow 1?, from the normal position P0 successively through the positions PI, P2, etc., and P5 during tne'sueces'sivecommend ing time intervals. Subsequently the wiper set 000 is rotated continuously during the secondary movement thereof in the clockwise direction, as indicated the arrow S, from the operated position PI, P2, etc., forwardly'teward the adjacent position P2, P3, etc., during the corresponding time intervals. 7 From an examination of the contact bank 500 shown in Fig. 5, it will be dndei'stood that, in order to operate the switch I00 to select the contact sets i I I2, etc., th wiper set 600 is first rotated the clockwise direction, during the primary movement thereof, from the normal position Ptlengagingthe contact selt 9'0 to the position P! t e a the qse et t 0" andis h tated in the clockwise direction, during the secondary movementthereo f, from the operated position I?! toward the adjacent position P2 to engage thecontact sets I I, I2, etc. Similarly, in order to operate the switch I00 to select the contact sets iii, 02, etc., the wi per set $00 is first rotated in the clockwise direction, during the primary movement thereof, from thenor'mal position; P0 engaging the contact set back to the position; P0 to engage the contact set 90, and is then rotated in the clockwise direction, during the secondary movement thereof, from the operated position P0 toward the adjacent position PI to engage the contact sets 0|, 02 etc. Ultimately, when the switch I00 is released the wiper set 000 is rotated in the clockwise direction from the engaged contact set back to the normal position P0 to engage the contact set 90.

Also the operating shaft I05 operates off-nopmal switch control mechanism illustrated diagrammatically as a cam 50I carried by the operating shaft I05 springs S505. The cam 50I comprises two pro jections 552 and 503 corresponding to the two normal positions of the wiper set 600; while the set ofswitch springs S505 comprises a set of contacts 506 which isengaged when the wiper set 600 occupies either one of its normal positions and a set of contacts 501 which is engaged when the wiper set 600 occupies other than one of its normal positions. This off-normal switch control mechanism is utilized in the switch I00, for a pur pose more fully explained hereinafter.

Referring now more particularly to Figs. 7 and 9 of the drawings, there are illustrated diagramrnatically a modified form of the wiper set 900 and the associated contact bank I00 of the switch whichmay be utilized when the gear train, shown in Fig, 2, is incorporated therein. More particularly, the wiper set 000 is carried by the operating shaft I05 and comprises a first section 90I, including a number of wipers 902, 903, etc., and a second section 9II, including a number of wipers BIZ, 0 I3, etc.; while the contact bank fIGII is of the I00-point type and comprises a first section 'IDI associated with the firstsection 90I of the wiper set 900 and a second section 102 associated with the second set:-

and an associated set of switch tion 9 of the wiper set 900. Preferably the first section 90I of the wiper set 900 is arranged above the second section 9 thereof; and the first section ml of the contact bank 100 is arranged above the second section 102 thereof. Each of the sections 10I and 102 of the contact bank 100 comprises five groups of contact sets; each group of contact sets comprises ten individual contact sets; and each individual contact set comprises a number of contacts. The contacts in each contact set in the first section 10I of the contact bank 100 are respectively associated with the wipers 902, 903, etc., of the first section 90I of the wiper set 900; while the contacts in each contact set in the second section 102 of the contact bank 100 are respectively associated with the wipers 9I2, 9I3, etc., of the second section 9II of the wiper set 900.

In this form of the switch I the wiper set 900 is rotated continuously during the primary movement thereof in the clockwise direction, as indicated by the arrow P, from the normal position P0 successively through the positions PI, P2, etc., and P9 during the successive corresponding time intervals. During this primary movement of the wiper set 900 the first section 90I thereof cooperates with the associated first section ml of the contact bank 106 in the positions P0, PI, P2, P3 and P4 and the second section 9II thereof cooperates with the associated second section 102 of the contact bank 100 in the positions P5, P6, P1, P8 and P9. Subsequently the wiper set 900 is rotated continuously during the secondary movement thereof in the counterclockwise direction, as indicated by the arrow S, from the operated position PI, P2, etc., back toward the adjacent position Pi), PI, etc., during the corresponding time intervals.

From an examination of the contact bank 100 shown in Fig. 7, it will be understood that, in order to operate the switch contact sets II, I2, etc., the wiper set 900 is first rotated in the clockwise direction during the primary movement thereof, whereby the first section 99I of the wiper set 900 is moved from the normal position P0 engaging the contact set I0 to the position PI to engage the contact set 20; the wiper set 900 is then rotated in the counterclockwise direction duringthe secondary movement thereof, whereby the first section 90I of the wiper set 900 is moved from the operated position Pl toward the .adjacent position P0 to engage the contact sets II, I2, etc. Similarly, in order to operate the switch I00 to select the contact sets I, 52, etc., the wiper set 900 is first rotated in the clockwise direction during the primary movement thereof, whereby the first section 90I of the wiper set 900 is moved from the normal position P0 engaging the contact set I0 to bring the second section 9 of the wiper set 900 to the position P5 to engage the contact set 60; the wiper set 900 is then rotated in the counterclockwise direction during the secondary movement thereof, where by the second section 9 thereof ismoved from the .operated position P5 and the first section .90I thereof is moved toward the adjacent position P4 to engage the contact sets 5|, 52, etc. In order to operate the switch I00 to select the contact sets 0!, 62, etc., the wiper set 900 is first rotated in the clockwise direction during the primary movement thereof, whereby the first section 90! of the wiper set 900 is moved from the normal position P0 engaging the contact set {B te bring these cond section SIIof the wiper I00 to select the set 900 to the position P6 to engage the contact set 10; the wiper set 900 is then rotated in the counterclockwise direction during the secondary movement thereof, whereby the sec-- end section 9 of the wiper set 900 is moved from the operated position P6 toward the adjacent position P5 to engage the contact sets BI, 62, etc. Similarly, in orderto operate the switch I00 to select the contact sets 0|, 02, etc., the wiper set 900 is first rotated in the clockwise direction during the primary movement thereof, whereby the first section 90I of the wiper set 900 is moved from the normal position P0 engaging the contact set I0 back to the position P0 to engage the contact set I0; the wiper set 900 is then rotated in the counterclockwise direction during the secondary movement thereof, whereby the first section Sill thereof is moved from the operated position P0 and the second section 9 thereof is moved toward the adjacent position P9 to engage the contactsets 0|, 02, etc. Ultimately, when the switch I00 is released the wiper set 900 is rotated in the clockwise direction from the contact set engaged by either the first section Bill or the second section 9| I thereof to bring the first section 90! thereof back to the normal position P0 to engage the contact set I0.

Also the operating shaft I05 operates off-normal switch control mechanism illustrated diagrammatically as a cam 10 I carried by the operating shaft I05 and an associated set of switch springs S105. The cam 'IOI' comprises a single projection 102' corresponding to the single normal position of the wiper set 900; while the set of switch springs S105 comprises a set of contacts 106 which is engaged when the wiper set 900 occupies its normal position, and a set of contacts 101 which is engaged when the wiper set 900 occupies other than its normal position. This off-normal switch control mechanism is utilized in the switch I00, for a purpose more fully explained hereinafter.

Referring now more particularly to Figs. 8 and 9 of the drawings there are illustrated diagrammatically a modified form of the wiper set 900 and the associated contact bank 800 of the switch I00 which may be utilized when the gear train, shown in Fig. 3, is incorporated therein. More particularly, the wiper set 900 is carried by the operating shaft I05 and comprises a first section 90I, including a number of wipers 902, 903, etc., and a second section 9| I, including a number of wipers 9I2, 9I3, etc., as previously noted; while the contact bank 800 is of the IOU-point type and comprises a first section I associated with the first section I of the wiper set 900 and a second section 802 associated with the second section 9I I of the wiper set 900. Preferably the first section 90I of the wiper set 900 is arranged above the second section 9II thereof; and the first section 80I of the contact bank 800 is arranged above the second section 802 thereof. Each of the sections 80I and 802 of the contact bank 800 comprises five groups of contact sets; each group of contact sets comprises ten individual contact sets; and each individual contact set comprises a number of contacts. The contacts in each contact set in the first section 80| of the contact bank 800 are respectively associated with the wipers 902, 903, etc., of the first section 90I of the wiper set 900; the contacts in each contact set in the second section 802 of the contact bank 800 are respectively associated with the wipers 9I2, 9I3, etc., of the second section 9| I ofthe wiper set 900.

In this form of the switch I the wiper set 900 is rotated continuously, during the primary movement thereof, in the clockwise direction, as indicated by the arrow P, from the normal position P0 successively through the positions PI, P2 etc. and P9 during the successive corresponding time intervals. During this primary movement of the wiper set 900 the first section iliil thereof cooperates with the associated first section 801 of the contact bank 800 in the positions P0, Pl, P2, P3 and P4, and the second section 9! I thereof cooperates with the associated second section 802 of the contact bank 800 in the positions P5, P0, P1, P8 and P9. Subsequently the wiper set 900 is rotated continuously during the secondary movement thereof, in the clockwise direction, as indicated by the arrow S, from the operated position P l P2 etc. forwardly toward the adjacent position P2, P3, etc. during the corresponding time intervals.

From an examination of the contact bank 800 shown in Fig. 8, it will be understood that, in order to operate the switch I00 to select the contact sets ii, I2 etc., the wiper set 900 is first rotated in the clockwise direction during the primary movement thereof, whereby the first section sill of the wiper set 900 is moved from the normal position P0 engaging the contact set 90 to the position PI to engage the contact 00; the wiper set 900 is then rotated in the clockwise direction during the secondary movement thereof, whereby the first section 9'0I of the wiper set 900 is moved from the operated position PI toward the adjacent position P2 to engage the contact sets I I, i2 etc. Similarly, in order to operate the switch I00 to select the contact sets EI, 52 etc, the wiper set 900 is first rotated in the clockwise direction during the primary movement thereof, whereby the first section 00I of the wiper set 900 is moved from the normal position P0 engaging the contact set 90 to bring the second section S'I I of the wiper set 900 to the position P to engage the contact set 00; the wiper set 900 is then rotated in the clockwise direction during the secondary movement thereof, whereby the second section 9|! thereof i moved from the operated position P5 toward the adjacent position P0 to engage the contact sets 5|, 52 etc. Similarly, in order to operate the switch I00 to select the contact sets 0!, 02 etc., the wiper set 000 is first rotated in the clockwise direction during the primary movement thereof, whereby the first section Bill of the wiper set 000 is moved from the normal position P0 engaging the contact set 90 back to the position P0 to engage the contact set 90; the wiper set 000 is then rotated in the clockwise direction during the secondary move ment thereof, whereby the first section 90! thereof is moved from the operated position P0 toward the adjacent position PI to engage the contact sets 0!, 02 etc. Ultimately, when the switch I00 is released the wiper set 900 is rotated in the clockwise direction from the contact set engaged by either the first section 90I or the second section 9 thereof to bring the first section '90I thereof back to the normal position P0 to engage the contact set 50. I

Also the operating shaft I05 operates oil-normal switch control mechanism illustrated diagrammatically as a cam 80 I carried by the operating shaft I05 and an associated set of switch springs S805. The cam 80I' comprises a single projection 802 corresponding to the single normal position of the wiper set 900; while the set of switch springs S805 comprises a set of com taots 006 which is engaged when the wiper set 900 occupies its normal position and a set of contacts 801 which is engaged when the wiper set 900 occupies other than its normal position. This off-normal switch control mechanism is utilized in the switch I00, for a purpose more fully explained hereinafter.

Referring now more particularly to Figs. 10 and 11 of the drawings there is illustrated an automatic telephone system comprising an exchange having a plurality of subscriber lines extending thereto, including the subscriber lines IO0I and I I 0| respectively extending to the subscriber substations TI and T2. Also the exchange comprises subscriber controlled switching apparatus for setting up connections between the various subscriber lines, the switching apparatus comprising a line switch individual to each subscriber line, the line switches I002 and H02 being individual to the subscriber lines IO0I and HM, respectively, and a group of connectors including the connector I 000. Preferably, each of the line switches has access to each of the connectors and each of the connectors has access to each of the subscriber lines in the exchange.

Preferably each subscriber substation comprises conventional subscriber substation apparatus including a telephone instrument, a ringer and a calling device or dial. Preferably each line switch is identical to the line switches I002 and II 02, which line switches are connected and arranged in accordance with conventional practice.

Preferably each of the connectors is identical to the connector I000 which comprises an automatic switch of the character of the automatic switch I00 shown in Fig. 1; which automatic switch has incorporated therein a gear train of the character of that shown in Fig. 2 and is provided with an associated contact bank of the character of that shown either in Fig. 4 or in Fig. 7 and a corresponding wiper set of the character of that shown either in Fig. 6 or in Fig. 9. In other words, the automatic switch incorporated in the connector I000 is of the type disclosed, wherein the wiper set thereof is advanced continuously during the primary movement thereof in the clockwise direction and then is advanced continuously during the secondary movement thereof in the counterclockwis direc tion, in the manner previously explained. Also this automatic switch comprises a go magnet MI056, a stop magnet MI051, a shift magnet MI058, three sets of switch springs SI035, SI036 and SI039, a wiper set including the wipers IIII lI'JIIS, inclusive, and an associated contact bank .fllso the connector I000 comprises a minor switch H20, including a slide H23, an associated contact bank I I 24, a step magnet MI I2I for movmg the slide I I23 step by step with respect to the associated contact bank I I24, and a release magnet MI I22 for releasing the slide H23 and for causing it to be returned to its normal position. Also a set of switch springs SI I25 is associated with the slide H23 of the minor switch II20,

Further the connector I000 comprises a relay group including a line relay RIOI0, a hold relay RI020, a dial relay Ri030, a first digit relay RI050 a second digit relay RIMS, a go relay RIOB0, a stop relay RI065, a test relay RIIH'O, an answer relay RI 015, switch-through relay RI080, a ring relay RI090 and a reset relay RI 005, and a control network.

In the connector I000 the circuit elements of the e y group are strapped to the individual wipers of the wiper set of the automatic switch and to certain elements of the minor switch H20. More particularly, the conductors CIOI I, CIOI2, CIOI3, CIOI4 and CIOI'5 are respectively strapped to the line wiper I I I I, the line wiper II I2, the control wiper III3, the unit wiper III4 and the group wiper I I I5 of the wiper set of the automatic switch; and the conductors CIOI6, CIO I! and CIOI8 are respectively strapped to the conductors CIIIB, CIIII and CIIIB extending to the minor switch I I20.

The mechanical construction and arrangement of the automatic switch I shown in Fig. 1, as well as the electrical connection and arrangement of the telephone system shown in Figs. 10 and 11, will best be understood from a consideration of the mode of operation of the apparatus incorporated in the system incident to the extension of a telephone connection from the subscriber substation TI to the subscriber substation T2.

A call is initiated at the subscriber substation TI by removing the receiver of the telephone instrument thereat from its associated switchhook, whereupon the line switch I002 operates automatically to search for a trunk extending to an idle connector in accordance with conventional practice. Assuming that the connector I000 is the first idle connector accessible to the line switch I002, the line switch I002 operates to seize the trunk I005 extending thereto, the trunk I005 being marked as idle by the absence of ground potential upon the control conductor CI008 thereof. When the line switch I002 seizes the trunk I005 further operation thereof is arrested and it operates to switch through, thereby to complete an obvious connection between the subscriber line IO0I and the line conductors CI006 and CI00'I of the trunk I005. When this connection is completed an obvious loop circuit is completed between the calling subscriber substation TI and the upper and lower windings of the line relay RIOI0 in the connector I000 by way of the subscriber line IO0I, the line switch I002 and the trunk I005. When thus energized the line relay RIOI 0 operates to complete, at the contacts IOI I, an obvious circuit for energizing the winding of the hold relay RI020, thereby to cause the latter relay to operate. Also the line relay RIOI0 completes, at the contacts IOI4, an

obvious circuit, including the contacts I06I, for energizing the winding of the stop relay RI 065 in series with the stop magnet MI'I, thereby to cause the stop relay RI065 to operate and to cause the stop magnet MI 051 to operate in order positively to lock the operating shaft I05 against rotation at this time. Upon operating, the hold relay RI 020 completes, at the contacts I022, an obvious path for applying ground potential to the control conductor CI008 of the trunk I005, thereby to mark the connector I000 as busy to the other line switches having access thereto. At this time anoperative connection is completed between the calling subscriber substation TI and the connector I000, and the connector I000 is in the circuit for energizing the upper and lower windings thereof in series is recompleted, in accordance with conventional practice. Upon restoring, the line relay RIOI0 interrupts, at the contacts ID, the previously mentioned circuit for energizing the winding of the hold relay RI020 and completes, at the contacts IOI2, an obvious path, including the contacts I023 and I043 and the conductors CIOI6 and CI I I6, for energizing the step magnet MI I2I of the miner switch II20. Also, upon restoring, the line relay RIOI0 completes, at the contacts IOI3, an obvious circuit, including the contacts I024, for energizing the winding of the dial relay RI030, thereby to cause the latter relay to operate. Also, upon restoring, the line relay RIOI0 interrupts, at the contacts IOI4, the previously traced circuit for energizing the winding of the stop relay RI065 in series with the stop magnet MI05'I, thereby to cause the stop relay RI065 to restore and to cause the stop magnet MI05'I to restore in order to release the operating shaft I05 for rotation at this time. Upon reoperating, the line relay RIOI0 recompletes, at the contacts IOI I, the previously mentioned circuit for energizing the winding of the hold relay RI020; interrupts, at the contacts IOI2, the previously traced circuit for energizing the step magnet MI I 2| of the minor switch I I20; and interrupts, at the contacts I0l3, the previously traced circuit for energizing the winding of the dial relay RI 030. Also the line relay RI 0I0, upon reoperating, prepares, at the contacts IOI4, the previously traced circuit for energizing the winding of the stop relay RI 065 in series with the stop magnet MI05'F; however, the last-mentioned circuit is not completed at this time due to the operated position of the 'go relay RI060, in a manner more fully explained hereinafter. Both the hold relay RI 020 and the dial relayRI 038 are of the slow-to-release type; accordingly these relays do not restore during impulsing.

Upon operating, the step magnet MI I2I of the minor switch II20 drives the slide, I123 one step, whereby ground potential i applied to the first contact in the associated contact bank H24 and th first marking conductor terminated thereby. The application of ground potential to the first marking conductor terminated by the first contact in the contact bank I I24 of the minor switch II20 completes a circuit, including the group wiper III5 and the engaged group contact of the contact set I0 in the contact bank II I0 0f the automatic switch, the conductor CIOI5 and the contacts I054, for energizing the winding of the go relay RI060 in series with the go magnet MI056. When thus energized the go relay RI060 operates to interrupt, at the contacts I06I, a point in the previously traced circuit for energizing the winding of the stop relay RI005- in series with the stop magnet Ml05I, as previous- 13; noted. Also the go relay R1060 interrupts, at the contacts I063, a point in a circuit traced hereinafter for energizing the release magnet MII22 of the minor switch II20. When thus energized the go magnet MI056 operates, thereby to clutch the stub shaft I40 to the operating shaft I05 of the automatic switch, in the manner previously explained.

When the slide H23 of the minor switch II20 is moved away from its normal position theset of switch springs SII25 is actuated, thereby to prepare the previously mentioned circuit for energizing the release magnet MI I22. Also when the automatic switch is operated the wiper set thereof is advanced in the clockwise direction line switches having access thereto.

with respect to the associated contact bank I I Ill. whereupon the sets of switch springs SI I135, SI 5338 ands I 035 are operated. More particularly, the set of switch springs SW35 is actuated into engage- -ment, thereby to complete an obvious alternative path for applying ground potential to the control conductor CIIJGB of the trunk I625, whereupon the trunk I605 is further marked as busy to the The set of switch springs SW39 is actuated into engagement, thereby to prepare a circuit traced here inafter for energizing the winding of the first digit relay EH56. Finally the set of switch springs SW36 is actuated, thereby to interrupt, at th contacts I838 thereof, a further point in an alternative circuit traced hereinafter for energizing the stop magnet MIME; and to prepare, at the contacts I 931 thereof, a further point in a circuit traced hereinafter for energizing the winding of the reset relay RHIr'lE in series with the go magnet MII.

In view of the foregoing explanation of the initial operation of the connector IBM, it will be understood that the line relay RIGID follows the first digit causing this digit to be registered by the step magnet MI I2I of the minor switch I I28. More particularly, the step magnet MI I2I is energized and subsequently deenergized a number of times corresponding to the first digit, whereby the slide H23 is operated a corresponding number of steps, whereupon ground potential is applied to a corresponding number of the contacts in the associated contact bank H24. As previously noted, the application of ground potential to the first contact in the contact bank H24 associated with the slide H23 of the minor switch H20 initiates operation of the automatic switch incorporated in the connector I 809, whereupon the wiper set is rotated in the clockwise directionwithrespect to the associated contact bank II II) of the automatic switch. At this point it is noted that the group contacts of the contact sets III, I9, I8, I'I, I6, I5, I4, I3, I2 and II in the contact bank IIIIl of the automatic switch are connected to the first marking conductor terminated upon the first contact in the contact bank H24 of the minor switch H20. Similarly, the group contacts of the contact sets 20, 29, 23, 21, 2'6, 25, 24, 23, 22 and 2| in the contact bank I I ill of the automatic switch are connected to the second marking conductor terminated upon the second contact in the contact bank H24 of the minor switch H2 2. Finally, in this connection, it is noted that the slide I I23 is of such a length that it is capable of simultaneously bridging not more than nine of the contacts in the associated contact bank H24 of the minor switch H29, for a purpose more fully explained hereinafter.

Considering now the extension of the call from the ca1ling subscriber substation TI to the called subscriber substation T2 in greater detail, it is noted that the subscriber line Hill extending to the called subscriber substation T2 is terminated upon the contact set it in the contact bank II II) of the automatic switch; accordingly the first digit dialed at the calling subscriber substation TI is 0 and the second digit to be dialed at the calling subscriber substation TI will be 8. Hence, the first digit 0 dialed at the calling subscriber substation Ti is registered in the minor switch H20 in the connector I039, as previously explained.

During the registration of the first digit 0 the minor switch H29 the automatic switch is operated, operation of the automatic switch beiii magnet MI 056 restore.

.ing initiated when the first impulse is registered in the minor switch H20, as previously noted. Accordingly when the first digit 0 is completely registered in the minor switch I I2!) the wiper set of the automatic switch has traversed a considerable number of the contact sets in the associated contact bank IIIII and occupies a position in engagement with some contact set well beyond the contact set 20, such, for example, as the contact set 93. At this time, when the first digit E) is completely registered in the minor switch H2?) the slide H23 thereof bridges the contacts 2 to 0, inclusive, in the associated contact bank I I24, but does not engage the first contact in the associated contact bank H24 due to the fact that the slide I I 23 is capable of bridging simultaneously only nine contacts in the associated contact bank, as previously noted. Hence, at this time, ground potential is applied by way of the slide I I 23 to each contact in the associated contact bank H24 with the exception of the first contact therein. Hence, ground potential is ap plied to the marking conductors terminated by the second through the tenth contacts in the contact bank I I24 of the minor switch H20 in order to cause continued operation of the automatic switch.

At the conclusion of the first digit 0 the line relay RIIlIfl reoperates, thereby to retain the hold relay RIOZICI in its operated position and to interrupt, at the contacts "M3, the previously traced circuit for energizing the winding of the dial relay RIDSil, whereupon the latter relay restores shortly thereafter, the dial relay EH38 being of the slow-to-release type. Upon restoring, the dial relay RI03I'I prepares, at the contacts IG3I, a further point in the previously men tioned circuit for energizing the winding of the first digit relay RIIIEII. Operation of the automatic switch incorporated in the connector I850 continues until the wiper set disengages the contact set BI and reengages the contact set It in the associated contact bank HIB, whereupon the previously traced circuit for energizing in series the winding of the g0 relay RIOGB and the go magnet MIilEfi is interrupted. The last-mentioned circuit is interrupted due to the engagement of the group wiper HI5 of the wiper set of the automatic switch with the group contact in the contact set III in the associated contact bank Hill, the ungrounded first marking conductor being terminated by the group contact of the contact set It in the contact bank IHIl, as previously noted. When the above-mentioned circuit for energizing the winding of the go relay RIilfiil in series with the go magnet MIBEie is thus interrupted, the go relay RIDGE] and the go Upon restoring the go relay RIQiiI) completes, at the contacts I855, the previously traced circuit for energizing the winding of the stop relay RIMS in series with the stop magnet MIEI5'I, thereby to cause the stop relay RIII and the stop magnet MI05l to operate. W'hen the go magnet MIII56 restores and the stop magnet MIOS'I operates the operating shaft I05 is declutched from the stub shaft ME], in the manner previously explained, thereby to arrest further movement of the wiper set of the automatic switch incorporated in the connector I800.

Also, upon restoring, the go relay RIlIGfi completes, at the contacts I062, the previously mentioned circuit for energizing the winding of the first digit relay RIBEII, this circuit extending from ground by way of the contacts I891, I862,

the set of switch springs SI039, the contacts I052 and I03I and the winding of RI050 to battery, whereupon the latter relay operates. Further the go relay RI060 completes, at the con tacts I053, the previously mentioned circuit for energizing the release magnet MI I22 of the minor switch H20. The last-mentioned circuit extends from ground by way of the set of switch springs SH25, CIH'I, CIOII, the contacts I063, CIOI8, CIIIB and the release magnet MH22 to battery. When thus energized the release magnet MI I22 operates in order to release the slide H23, whereupon the slide H23 is returned to its normal position. When the slide H23 is thus released the set of switch springs Si I25 is actuated into disengagement, thereby to interrupt the above-traced circuit for energizing the release magnet MI I22, whereupon the latter magnet restores. At this time the minor switch I I20 is completely released.

. Upon operating, the first digit relay R! I350 completes, at the contacts I05I, an obvious holding circuit, including the contacts I02I, for energizing the winding thereof, interrupts, at the con circuit for energizing the shift magnet MI058,

thereby to cause the latter magnet to operate in order to render effective the gear train shown in Fig. 2 incorporated in the automatic switch provided in the connector iii0, in the manner previously explained. At this time the connector I003 is in readiness to receive the second digit 8.

The subscriber at the calling subscriber substation Tl then dials the second digit 8, thereby to cause the line relay Riilill to follow in the manner previously explained. The line relay RiII] repeats, at the contacts Hill, the second digit 8 over the previously traced circuit to the step magnet MHZI of the mnior switch H20, whereby the slide H23 registers the second digit 8 in the associated contact bank H24 of the minor switch H20, in the manner previously explained. Also the line relay RIIIIIi repeats the second digit 8 at the contacts II3 to the dial relay RIii'il, thereby to cause the latter relay to operate and remain operated during impulsing, in the manner previously explained. Upon operating, the dial relay Ri 030 completes, at the contacts I032, a circuit, including the contacts I02I and I05l and the resistor I034, for energizing the winding of the second digit relay RIMI). When the above-traced circuit is completed the second digit relay RIMI] operates partially shortly thereafter, the second digit relay RIMI! being of'the combination slow-to-operate and marginal type.

Upon operating partially, the second digit relay RiMil prepares, at the contacts I042, an alternative circuit traced hereinafter for energizing the winding thereof; the last-mentioned circuit being interrupted at this time, at the contacts I033, due to the operated position of the dial relay I030.

When the registration of the second digit 8 in the minor switch I529 is initiated the slide H23 bridges the first eight contacts in the associated contact bank H24, thereby to cause ground pominor switch H20 at this time.

tential tobe applied to the associated marking conductors in the manner previously explained. The application of ground potential to the first contact in the contact bank H24 of the minor switch H20 and consequently to the first marking conductor completes a circuit, including the unit wiper II I4 of the wiper set and the engaged unit contact of the contact set I0 in the associated contact bank IHO of the automatic switch, CIOI4 and the contacts I053, for energizing the winding of the go relay RI000 in series with the go magnet MI056, thereby to cause the go relay RIIIBU and the go magnet MI050 to operate. Upon operating, the go relay RI060 interrupts, at the contacts I06 I the previously traced circuit for energizing the winding of the stop relay RI 065 in series with the stop magnet MI05'I, thereby to cause the stop relay RI065 and the stop magnet MI05'I to restore. When the stop magnet M051 restores and the go magnet MI056 operates the operating shaft I05 is again clutched to the stub shaft I40, whereby the Wiper set'of the automatic switch is moved in the counterclockwise direction with respect to the associated contact bank I I I0, in the manner previously explained. Also, upon operating, the go .relay R050 interrupts, at the contacts I062, a further point in the previously traced operating circuit for energizing the winding of the first digit relay RI050, and interrupts, at the contacts 1063, the previously traced circuit for energizing the release magnet MI I22 of the minor switch H20.

When the second digit '8 is registered in the minor switch I I 20 the set of switch springs SI I25 is operated, thereby to prepare a point in the previously traced circuit for. energizing the release magnet MII22. Also the unit contacts in the contact sets I0, 0|, 02, 03, 04, 05, 06 and 01 in the contact bank H|0 of the automatic switch are marked with ground potential, thereby to complete alternative circuits for continuing the energization of the winding of the go relay RI060 in series with the go magnet MI 056, whereby operation of the wiper set of the automatic switch is continued.

At the conclusion of the second digit 8 the line relay RI 0 I 0 reoperates, thereby to retain the hold relay RI020 in its operated position and to effect the restoration of the dial relay RI030 shortly thereafter, the dial relay R1030 being of the slow-to-release type. Upon restoring, the dial relay RI030 completes, at the contacts I033, the previously mentioned alternative circuit for energizing the winding of the second digit relay RI040, the last-mentioned circuit extending from ground by way of the contacts I02I, I05I, I042 and I33 and the winding of RI040 to battery. Shortly after the second digit relay RI040 is thus energized it operates completely as it is of the combination slow-to-operate and marginal type, as previously noted. Upon operating completely the second digit relay RI040 completes, at the contacts I04I, a holding circuit, including the contacts I042, |05I and I02I, for energizing the winding thereof. Also the second digit relay RI040 interrupts, at the contacts I 043, a further point in the previously traced circuit for energizing the step magnet MHZI of the minor switch H20, thereby positively to prevent the registration of further digits in the Finally the sec ond digit relay RI040 completes, at the contacts I044, either a circuit for energizing the winding of the switch-through relay RI000 in series with the lower Winding of the test relay 

